A telecommunications network is often modeled as a graph, with a vertex representing a network element physical location, and an edge representing a link over which data can be transmitted. This simple model does not capture the complex layered nature of many networks, where a logical link used by one technological level is provided as a service by a different level.
U.S. patent application Ser. No. 10/900,561, filed Jul. 28, 2004, entitled “System and Method for Verifying a Description of a Network,” incorporated by reference herein discloses a network model that explicitly captures the layered nature of networks. The disclosed model is based on the concepts of layering and adaptation. A layer is a particular encoding of a stream of data. Adaptation is the conversion between layers. Adaptation models both encapsulation and multiplexing. An instance of the model includes links that transmit data and adapters that perform adaptation.
The disclosed model can be applied uniformly and simultaneously to many network technologies, such as Synchronous Optical Network (SONET), Asynchronous Transfer Mode (ATM), Dense Wavelength Division Multiplexing (DWDM) and Multi Protocol Label Switching (MPLS). An instance of the model represents the flow of data through a network, where communication at one layer may depend upon links at a different layer. The model forms the conceptual basis of NetML, an XML-based network interchange language. NetML can be used to implement many standard network analysis algorithms, such as circuit tracing, shared protection analysis, reliability estimation and fault analysis, in a way that is independent of technology.
While NetML effectively allows most types of networks to be modeled, it does not provide a mechanism for automatically comparing two different network models. In particular, NetML does not provide techniques for determining equivalence and generalization of network models. Thus, a need exists for methods and apparatus for determining equivalence or generalization (or both) of network models.